The subterranean medium is the sixth dimension, next to the ground, the air, the sea, outer space and cyberspace. Operational conduct in the subterranean medium conforms to different rules and involves unique methods of operation. In the subterranean medium, a person can easily lose his senses: you cannot see, you cannot hear. It takes time to adjust, to learn what's down there, to start getting your bearings and find your way in the underground space. It takes time to spot the tunnel, access it, drill, excavate and rappel into its depths. But spotting the tunnel is not the end of it. Once spotted, the questions arise: where is it heading? To the right? To the left? How long is it? What's in it? Who's in it?
Each tunnel has a story: its structure, length, size and depth, wall shape, the equipment it contains. What did the excavators have in mind when they excavated it in this particular way and not differently? Is it a defensive tunnel? An offensive tunnel? Is it an explosive tunnel or a fighting tunnel? What is its heading? Where are its openings?
The senior IDF officer who commanded tunnel-related operations in the Gaza Strip and more recently, during Operation Northern Shield along the border with Lebanon, tells us about the mysteries of the subterranean medium and the tunnels. The IDF Chief Engineering Officer, Brig. Gen. Ilan Sabag, commanded the YAHALOM Unit (a special assignment engineering unit) and other units in the operation during which IDF spotted and destroyed Hezbollah tunnels along the Lebanon border.
Right at the outset, the Chief Engineering Officer clarifies: "In conclusion of the operation, we can report the spotting of six spatial routes (the IDF jargon for underground tunnels – D.A.). Two of the tunnels were blasted using explosives, and we poured massive amounts of concrete into two other tunnels. Filling the tunnels with concrete was a project that lasted a few days. We use specialized equipment and pouring devices in order to push concrete deep into the tunnel. The thickness of the concrete inside the tunnel is between dozens and hundreds of meters, so the tunnels we spotted and destroyed in this way can no longer be used. The entire operation was conducted under adverse weather conditions and with everyone involved showing tenacious perseverance and determination.
We met with Brig. Gen. Sabag late in the evening at the HQ of the YAHALOM Unit, at their permanent base in the central region. In the next room, the deputy commander of the YAHALOM Unit showed us a video clip taken from a drone – the controlled blasting of 600 landmines in Qasr al-Yahud, the Land of Monasteries, close to the border with Jordan. It was just a drop in the vast ocean, as Israel is surrounded by about one million landmines that must be cleared – the remnants of past conflicts. The clearing of mines is the responsibility of the Landmine Branch, Combat Engineering Corps HQ, which cooperates with the Israel Mine Action Authority – a civilian organ belonging to IMOD. The combined effort is intended to ensure that one day, the State of Israel will be free of landmines.
"A Military Occupational Specialty"
Operation Northern Shield was based on lessons learned from tunnel-related operations in the Gaza Strip. Since 2006, 15 tunnels were spotted and destroyed in the south – seven tunnels in 2007 alone. The YAHALOM Unit and the Engineering HQ at IDF Southern Command were responsible for all of these operations. According to Brig. Gen. Sabag, "Spotting and destroying the tunnels and the specialized technologies developed for this activity are a part of the doctrine we teach to our warfighters and commanders, which is, essentially, to deny the enemy of the initiative.
"Addressing the subterranean medium and the tunnel issue demands that the elements involved enjoy a degree of latitude that is unlike anything that exists above ground. This activity involves a combination of capabilities, resources, technologies and techniques, the ability to improvise when faced with complex problems, and above all – professionalism. Today, everyone has already acknowledged the fact that subterranean warfare is a military occupational specialty – just like any other military specialty. We teach that specialty in all of the elements of the Combat Engineering Corps – from basic training to commander training courses."
The IDF Combat Engineering Corps is the element in charge of formulating and implementing the combat doctrine for subterranean warfare. The warfighters currently use specialized installations for subterranean warfare training, and the various training courses, at all levels, implement the types of equipment, weapon systems, infrastructures and prepare regular and reserve personnel for the task.
Operation Northern Shield was extensively covered by the media in Israel and overseas, but it started out in complete secrecy. Brig. Gen. Sabag says "It all started on the night of the Second Candle, during the Hanukkah holiday. We had the base of the YAHALOM Unit locked down completely – no one goes in or out. All leaves canceled. We collected all of the mobile phones. No outgoing calls. The battle procedure was very short and the units departed for the north. Around the town of Metula, there was an impressive concentration of forces: Combat Engineering Corps, IDF Northern Command, the regional division, IDF brigades, earth-moving equipment, engineering officers, technical laboratories, C4I. The commander of the northern division had assembled an extensive range of forces. The YAHALOM Unit and the commander of the Engineering HQ at IDF Northern Command conducted the engineering operation. The motto was self-evident: 'We do not leave until we find a tunnel,' and we operated under the inspiration of the order issued by the Chief of Staff to 'turn every tunnel into a death trap.' Any enemy element located in the subterranean medium should either die inside or come out and fight us."
"The Realm of Uncertainty"
The people of the Combat Engineering Corps distinguish between five tunnel categories: border-crossing offensive tunnels, administrative tunnels, smuggling tunnels (mainly in the Gaza Strip), tunnels serving both offensive and defensive purposes, and explosive tunnels.
On several occasions, the IDF encountered explosive tunnels. In these tunnels, massive amounts of explosives are cached to generate a blast that might be lethal to units located around the tunnel. This happened prior to Operation Pillar of Defense in the Kissufim sector, when 70 kilograms of explosives were detonated in a tunnel that crossed the border from the Gaza Strip into Israel. In another incident, near an IDF post facing the Gaza Strip, hundreds of kilograms of explosives were detonated inside an explosive tunnel. Preparations for the excavation of an explosive tunnel were uncovered and drums intended to store the explosives were found inside the tunnel.
The YAHALOM Unit has been leading the subterranean and tunnel activity since the year 2000. The tunnel unit was named SAMUR (= Weasel). Sabag was the commander of an engineering battalion based in Nahal-Oz in the years 2000-2003. "We searched for tunnels in Rafah. We would go into a house, open up the floors and look for tunnels, being particularly cautious about explosive tunnels. In those days, we searched through the subterranean medium with our eyes and hands – the technology did not yet exist back then."
Since then, a special company was established within the YAHALOM Unit and the Combat Engineering Corps started developing capabilities. This effort led to the development of five unique engineering activities: the YAEL Reconnaissance Unit, specializing in engineering reconnaissance; the SAMUR unit, specializing in the subterranean medium and tunnels; the bomb disposal unit; a troop specializing in house breaching operations and the SAYFAN (= Gladiolus) Unit, specializing in biological and chemical warfare.
Following a basic training period, the Combat Engineering warfighter starts acquiring the sapper's specialized skills. The Corps' selection system will assign him to one of the five activities outlined above. The subterranean activity is rated high on the scale of priorities. Warfighters are trained to operate in tight, enclosed spaces by practicing inside a pipe. During the more advanced stages of their training program, warfighters actually go deep into the ground at a specialized training facility. Brig. Gen. Sabag describes the training stage: "The depth element is not natural to human nature. We were born to walk the earth, not to operate underground. The subterranean environment is the realm of uncertainty. Sometimes, you are there on your own. You are the first to slide in, as someone has to rappel down the narrow hole into the tunnel just spotted, and you never know what – or who – is waiting for you down there.
"Initially, you rappel on your own and enter the tunnel fitted with a breathing apparatus. During the training period, the trainees learn how to adjust quickly to a claustrophobic environment so that the warfighter will not lose control. In fact, you are moving inside a pipe and must possess a presence of mind, the ability to operate independently and pick out, in the dark, small details of what the tunnel contains. In some cases, the terrorists detonated explosive charges against the detachment of the SAMUR Unit operating inside the tunnel. In other cases, they detonated explosives during the drilling stage – while we were drilling into the tunnel, and we had casualties."
Once the technological resources have spotted the existence of a tunnel, the warfighters of the Combat Engineering Corps apply their unique subterranean medium skills: rappelling (into the tunnel), climbing (out of the tunnel) and extrication (in the event that there are casualties to be taken out of the tunnel). During the rappelling and climbing stages, the warfighters use a specialized tripod weighing a few dozen kilograms.
Brig. Gen. Sabag has been commanding the Combat Engineering Corps for two years. He was born in 1970 in Dimona, and must have served in all of the positions that exist along the chain of command of the small, intimate corps where everyone knows everyone else. Sabag served as the commander of an engineering battalion, as deputy commander of the YAHALOM Unit, as commandant of the IDF Combat Engineering Training School and as commander of the Engineering HQ at IDF Southern Command. He has served as the IDF Chief Combat Engineering Officer since August 2017. During his career, he had a chance to don the red helmet and rappel deep into freshly-spotted tunnels on more than one or two occasions.
The Gray Beret Revolution
The core of the Combat Engineering Corps consists of the three engineering battalions, of which at least one, the 601st (Assaf) Battalion, is as old as the IDF itself. The other battalions are the 603rd (Lahav) Battalion and the 605th (HaMahatz) Battalion. The specialist units complement the order of battle of the Combat Engineering Corps: the YAHALOM Unit, an earth-moving equipment company, the YAEL Reconnaissance Unit, the robotics troop, the SAYFAN (biological-chemical warfare) troop and the Combat Engineering Training School.
The Chief Engineering Officer and the Corps HQ are currently leading an actual revolution within the Combat Engineering Corps. Essentially, the process is intended to adapt the Corps to the present era, to the modern battlefield and to the modes of battle and combat tactics expected in the future, to periods of 'the war between wars' and to urban warfare. The motto of the engineering revolution in the IDF: assured uninterrupted engineering support throughout the combat zones.
Sabag lists the highlights of the revolution, telling us that the engineering officer, his troopers and their equipment, at any level, must provide solutions for all modes of battle, under any conditions, anytime and anywhere. They may be called upon to provide engineering support to maneuvering forces deep inside enemy territory; to handle subterranean medium challenges; to employ explosives; to neutralize IEDs; to demolish enemy infrastructures; to clear enemy positions; to engage in combat engineering operations while cooperating closely with a maneuvering infantry or armored battalion, and to provide close engineering support on the way to the objective as well as on the objective. Sappers and dozer/excavator operators will be called upon to clear a passage between houses in enemy territory so that the warfighters may advance through a built-up area. Engineering units participate in border protection operations by preparing infrastructures in border areas for the construction of posts and firing positions.
The engineering NAMER is the relatively new armored personnel carrier of the Combat Engineering Corps – a dedicated modern platform designed to support the operations of the engineering forces and ensure mobility and trafficability on the ground. The 603rd Battalion is already equipped with the engineering NAMER APC. The other engineering battalions will receive this dedicated platform in the context of the long-term plan of the IDF.
The NAMER APC, along with other vehicles and the various types of earth-moving platforms enable the engineering units operating on the modern battlefield to negotiate and clear obstacles and clear passages. They offer landmine planting/clearing and booby trap laying/clearing capabilities, the employment of breaching resources and bridging/crossing equipment used over narrow waterways and ditches (assault bridging). The warfighters of the YAEL Reconnaissance Unit possess assault bridging/crossing capabilities. The Combat Engineering Corps employs robotic platforms extensively, from robotic dozers to small robotic vehicles that facilitate breaching into houses or robots for handling roadside explosive charges.
"The Corps currently trains warfighters for five main activity categories: sappers, YAHALOM, earth-moving, bridging and biological-chemical warfare," explained Brig. Gen. Sabag. "The motivation to join the Combat Engineering Corps is definitely on the rise. There is a demand for service in the Combat Engineering Corps owing to the tendency among young recruits to serve in a corps that combines combat duty with technology. The Combat Engineering Corps currently serves as a national knowledge center for the activities outlined above, mainly with regard to the subterranean medium and tunnels. Operation Northern Shield has definitely encouraged new recruits to join our ranks, and there is a demand for service with the YAHALOM Unit, as this unit made the headlines recently. The officers in our Corps are highly capable, intelligent and motivated individuals. We were recently granted an allotment for three engineering officers to enroll in a two-year study program with the IDF Tactical Command College. I had a hard time selecting the candidates as all our officers are excellent, devoted and highly professional individuals."
Sabag had some special compliments for the operators of earth-moving equipment: "When I served as a battalion commander in the Kerem-Shalom and Nahal-Oz sectors, I experienced situations where IDF warfighters encountered complex enemy IED setups. In such cases, you call in a heavy dozer/excavator to clear the IEDs. You must have a substantial dose of courage to approach and lower the shovel of your dozer/excavator on the IED setup, or handle an IED buried under a tank. The dozer/excavator operator lowers the shovel and he will be the first one taking in the blast. In many cases, the dozer/excavator operators are the advance guard, as they are the first to advance into an area saturated with enemy elements. Such a dozer/excavator constitutes a gigantic target, moving at a speed of one kilometer per hour.
"It takes some courage to sit there in the dozer/excavator during combat. In some cases, the dozer/excavator was busy uncovering a freshly-spotted tunnel and the enemy tried to pick out the dozer/excavator operator in order to hit him. Dozer/excavator operators may be called upon to clear a passage between two houses in urban warfare areas. These operators must be saying to themselves 'We are the first to enter and the last to leave,' as they must 'reshape' the space before the forces leave."